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UNiTE sara JOHN F. SGHUYLER, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO WM. E. LOCKWOOD,

OF SAME PLACE.

APPARATUS FOR DRESSING GRINDSTONES.

Specification of Letters Patent No. 28,639, dated June 5, 1860'.

To all whom it may concern:

Be it known that I, JOHN F. SOHUYLER, of the city and county of Philadelphia, State of Pennsylvania, have invented a new and Improved Apparatus for Dressing Grindstones; and I do hereby declare the following to be a full, clear, and exact description of the same, reference being had to the accompanying drawing and to the letters of reference marked thereon.

My invention consists of a wheel composed of a series of radiating sharp edged chisels situated between two yielding washers the whole being arranged, and hung to a handle substantially in the manner described hereafter so as to form an instrument which, on application to the surface of a revolving grindstone, will impart a number of indentations to the same, without injuring the points of the chisels.

In order to enable others to make and use my invention, I will now proceed to describe its construction and operation.

On reference to the accompanying drawing which forms a part of this specification, Figure l, is a side view of my improved instrument for dressing grindstones. Fig. 2, a sectional view, and Fig. 3, an edge view partially in section.

Similar letters refer to similar parts throughout the several views.

(A) represents a portion of an ordinary grindstone, and (B) a stationary bar on which rests the edge of my improved dressing apparatus. The latter consists of a handle or stem (C) having at the lower end an opening or slot (c) within which, and on a pin (D), revolves the dressing wheel as seen in Fig. 8. This wheel consists of the two hubs (e) and (f), (the former screwing into the latter,) a central washer (7L) with a series of radiating chisels (i), sharpened at the end, and the two washers (j j) of gum, cloth, or other suitable yielding material. The chisels are simply let into recesses in the central washer (h) so as to be readily removed therefrom, the whole with the washers being securely confined between the hubs (e) and (f) and the diameter of the yielding washers being such that their edges shall project beyond the points of the chisels to a slight extent.

In applying my improved dressing apparatus, the handle or stem is held firmly in a vertical, or nearly vertical position, the lower end resting on the stationary bar (B) and the lip (m) attached to the handle, serving to maintain the latter in its proper position on the bar. The upper end of the handle is then moved gradually forward so as to bring the peripheries of the yielding washers (j in contact with the grindstone, care being taken to keep the points of the chisels free from Contact with the stone in the first instance. The handle and its wheel are held in this position until the revolving stone communicates a rapid rotary motion to the dressing wheel, when the latter is moved by the handle still farther toward the stone until the edges of the chisels bear against and indent the surface. ,After being thus held for some time the chisels have imparted such a number of indentations that the stone is fully dressed and ready for use in sharpening knives and other objects.

The object of the yielding washers is to preserve the ends of the chisels, for should the points of the latter be brought in imy mediate contact with the edge of the revolving stone without any previous rotary motion being imparted to the wheel, the stone would, during its first efforts to turn the wheel, have such a grinding effect on the ends of the chisels that their points would be worn and become of little or no use in making the desired indentations.

I claim as my invention and desire to secure by Letters Patent- The within described dressing wheel composed of a series of radiating sharp pointed chisels situated between two yielding washers, the whole being arranged and hung to the stem (C), or its equivalent, substantially in the manner and for the purpose herein set forth.

In testimony whereof, I have signed my name to this specification, in the presence of two subscribing witnesses.

JOHN F. SGHUYLER.

l/Vitnesses:

HENRY I-IowsoN, CHARLES D. FREEMAN. 

